- Email: [email protected]
Effect of pelleted high-oil canola meal from on-farm biodiesel production on rumen fermentation in lactating Holstein dairy cows
The Professional Animal Scientist 27 (2011):29–34
©2011 American Registry of Professional Animal Scientists
E fcanola fect of pelleted high-oil meal from on-farm
biodiesel production on rumen fermentation in lactating Holstein dairy cows H. A. Maiga,*1 D. M. Harris,* M. E. Meyer,* C. R. Dahlen,† and M. L. Bauer† *Department of Agriculture, Animal Science Division, University of Minnesota, Crookston 56716; †Department of Animal Sciences, North Dakota State University, Fargo 58108-6050
ABSTRACT Four lactating, ruminally cannulated Holstein cows (DIM ≥50; ≥second lactation) were paired by milk production and used in a switchback design to compare ruminal fermentation response to a diet containing 7% pelleted, high-oil canola meal (HOCM) versus a control diet (CONT). The CONT diet was made of corn silage, alfalfa haylage, wheat straw, and the concentrate. The HOCM diet contained the same ingredients as the CONT except sunflower seeds and a portion of soybean meal were replaced with pelleted, high-oil canola meal in the concentrate. The canola pellet contained 16.6% crude fat and 37.3% CP. Diets were formulated to be isonitrogenous and isocaloric. The last day of each 21-d switchback period was used to collect ruminal fermentation data. Ruminal fluid samples were collected through the cannula at 0, 2, 4, 6, and 8 h after feeding. Cows were housed in a tie-stall barn, and diets were delivered as a TMR once daily at 1000 h to achieve ad libitum intake (5% orts). Daily DMI and milk producCorresponding author: [email protected]
1
tion data were recorded during the entire feeding period. There were no differences (P ≥ 0.29) between DMI, milk yield, and efficiency of milk production of cows fed the HOCM and the CONT diets. Ruminal acetate, butyrate, total VFA, and pH were not affected (P ≥ 0.37) by diets. Ruminal propionate tended to be greater (P = 0.09) in cows fed HOCM. Adding 7% of pelleted, high-oil canola meal to lactating Holstein dairy cow diets did not adversely affect ruminal fermentation. Key words: biodiesel coproduct, lactating dairy cow, pelleted high-oil canola meal, ruminal fermentation
INTRODUCTION The increasing need for energy production has generated interest in small-scale on-farm biofuel production from oilseed crops. Specifically, the growing demand for biodiesel has provided the opportunity to crush canola seed for this purpose. In 2006, several farmers in Minnesota and Wisconsin began crushing canola with small-scale on-farm oilseed presses. The mechanical process removes oil
from the seed with the coproduction of a protein pellet that contains greater concentrations of residual oil compared with solvent-extracted canola meal. The protein pellet obtained from our pilot production plant contained 16.6% crude fat and 37.3% CP (DM basis). The daily quantity of protein pellet produced was 320 kg or 115 t yearly per processing unit. The use of the term canola meal throughout the text refers to low-fat canola meal, either solvent or mechanically extracted. In contrast, commercially available, solvent-extracted canola meal contains less ether extract (4%), which is higher than other oilseed meals because of inclusion of 1.5% of gums (Sanchez and Claypool, 1983). Sanchez and Claypool (1983) also reported that the protein content of canola meal varies from 35 to 39% depending on the cultivar used. The amino acid profile of the RUP fraction of canola meal mimics the milk protein amino acids, and the RDP fraction may stimulate microbial growth in the rumen (Piepenbrink and Schingoethe, 1998). The pelleted high-oil and high-
30 protein canola meal contains slightly more energy (2.43 Mcal/kg) in terms of NEl at 3 times maintenance intake than does soybean meal (2.13 Mcal/ kg; NRC, 2001) or canola meal (1.57 Mcal/kg; NRC, 1989). Regular canola meal is an excellent and safe protein supplement for dairy cows (Bell, 1984; Maesoomi et al., 2006) compared with its parental rapeseed meal. To our knowledge, no studies have been conducted on this novel biodiesel coproduct feed ingredient. The objective of this study was to evaluate ruminal VFA, pH, and ammonia-concentration responses to a diet containing 7% pelleted, high-oil canola meal versus a control diet, when diets were balanced to be isonitrogenous and isocaloric. We hypothesized that ruminal fermentation response of cows fed the 2 diets would be similar.
MATERIALS AND METHODS Animals and Treatments The use and handling procedures of animals used in this study were approved by the University of Minnesota Animal Care and Use Committee. Four lactating, ruminally cannulated
Maiga et al.
Holstein cows (DIM ≥50) in second or higher lactation were paired by milk production (≥30 kg/d) and assigned to one of 2 diets in a switchback design (Lucas, 1956; Lucas, 1960) of 2 periods of 21 d each. The ingredient composition of the diets is presented in Table 1. The forage portion of the control (CONT) diet contained alfalfa haylage, corn silage, and wheat straw and the concentrate portion contained rolled, high-moisture corn, soybean meal, sunflower seeds, dried distillers grains with solubles, minerals, and vitamins. The pelleted, high-oil canola meal (HOCM) diet contained the same ingredients as the CONT diet except sunflower seeds and a portion of soybean meal were replaced with pelleted, high-oil canola meal. The pellet contained 16.6% crude fat and 37.3% CP. Diets were formulated to contain 18% CP and 1.74 Mcal/kg of NEl, which called for a 7% canola meal inclusion rate in the HOCM diet. Diets were also formulated to provide a similar amount of total crude fat. Cows were housed in a tie-stall barn, and diets were delivered as a TMR once daily at 1000 h to achieve ad libitum intake (5% orts). Amounts of feed fed and orts were recorded daily to determine DMI.
Table 1. Ingredients composition of TMR for cows fed the control or the pelleted, high-oil canola meal (HOCM) diets Ingredient, % of dietary DM Alfalfa haylage Corn silage Wheat straw High-moisture corn (73.3% DM) Soybean meal (44% CP) Sunflower seed Dried corn distillers grains Pelleted canola meal (expeller) Dicalcium phosphate (CaHPO4) Sodium bicarbonate (NaHCO3) Calcium carbonate (CaCO3) Trace-mineralized salt1 Vitamin ADE2
Control
HOCM
25.0 25.0 2.0 21.1 13.0 2.8 8.5 — 0.3 1.0 0.5 0.6 0.2
24.9 24.9 2.0 21.0 9.1 — 8.5 7.0 0.3 1.0 0.5 0.6 0.2
Provided per kilogram of dietary DM: 36.5 mg of Zn, 26.0 mg of Mn, 20.5 mg of Fe, 9.1 mg of Cu, 0.6 mg of I, 0.4 mg of Co, and 0.3 mg of Se.
1
Provided per kilogram of dietary DM: 6,875 IU of supplemental vitamin A, 1,379 IU of supplemental vitamin D, and 23 IU of supplemental vitamin E.
2
Sample Collection and Chemical Analyses Samples of TMR, alfalfa haylage, corn silage, wheat straw, concentrates, and pelleted canola meal were collected once weekly during each feeding period and frozen at −20°C until analysis. Samples were oven dried at 55°C and ground through a Wiley mill (1-mm screen; Arthur H. Thomas, Philadelphia, PA). All samples were analyzed for DM, CP, ether extract, ash, ADL, calcium, and phosphorus (methods 930.15, 990.02, 945.16, 942.05, 973.18, 968.08, and 965.07, respectively; AOAC, 1997). The NDF (with amylase and without sulfite) and ADF were analyzed with a fiber analysis unit (Ankom Technology, Fairport, NY) using the procedure of Van Soest et al. (1991). Samples of whole ruminal contents (about 200 mL) were collected through the cannula from the ventral sac of the rumen of the 4 cows on d 21 of each period. Samples were taken at 0, 2, 4, 6, and 8 h relative to feeding. Samples were strained through layers of cheesecloth, followed immediately by pH measurement of ruminal fluid using a sealed electrode (Orion Research model 701A meter, Waltham, MA). A 50-mL ruminal fluid sample was frozen for later determination of VFA and ammonia. Ammonia concentration at each sampling hour was determined by colorimetric procedure (procedure 640 with urease hydrolysis omitted, Sigma Chemical Co., St. Louis, MO), and VFA were determined by GLC as described by Chichlowski et al. (2005). Daily DMI and milk production data were recorded during each feeding period. Cows were milked twice daily, and milk weights were recorded at each milking during the entire trial period. To eliminate carryover effects of diets, only data from the last 14 d of each period were used to determine DMI and milk yield.
Effect of pelleted high-oil canola meal on rumen fermentation
Table 2. Chemical composition of control and high-oil canola meal (HOCM) diets and the pelleted, high-oil canola meal (DM basis) Item DM, % CP, % NEl,1 Mcal/kg Ether extract, % NDF, % ADF, % Lignin, % NFC,2 % Ash, % Ca, % P, % 1
Control
HOCM
Canola meal pellet
57.1 18.1 1.74 4.8 28.7 17.6 3.7 41.1 7.3 0.96 0.48
57.3 18.2 1.74 4. 7 28.8 17.8 3.8 41.0 7.5 0.95 0.49
92.9 37.3 2.43 16.6 18.5 14.3 8.7 22.3 5.3 0.45 0.76
Calculated using NEl equations for feedstuffs from NRC (2001).
NFC (nonfiber carbohydrates) = 100 − (% NDF + % CP + % fat + % ash) according to the NRC (2001) model.
2
31
(DePeters and Bath, 1986) or 14% canola meal (Chichlowski et al., 2005; Maesoomi et al., 2006). However, Brito and Broderick (2007) found a 0.70 kg/d greater DMI by Holstein cows fed 16% canola meal than by cows fed 12% soybean meal but no difference in milk yield between the 2 treatments. Milk production of Holstein cows fed 11.7% canola meal was similar to that of cows fed 10.4% cottonseed or 8.6% soybean meal (Sanchez and Claypool, 1983).Yield of milk components was not affected by canola meal (DePeters and Bath, 1986; Chichlowski et al., 2005). Milk production efficiency (kg of milk/kg of DMI) was not different (P = 0.54) among diets.
Ruminal VFA Return over Feed Cost Calculation The cost–benefit analysis method (Maiga et al., 1995) was used to determine returns on feeding the HOCM diet versus the CONT diet. The difference between the daily revenue (benefit) and the cost is the return on feeding a given diet. Return over feed cost was calculated by using local prices of feed ingredients and milk price received for milk sold at the time of the study. The pelleted, high-oil canola meal was priced based on local average price of commercially available solvent-extracted canola meal relative to its NEl with the assumption that both canola meals would have similar protein content. Revenue from both diets was calculated by multiplying the average quantity of milk produced by the 4 cows times milk price. Feed cost was calculated by multiplying the average quantity of DMI of the 4 cows times the daily cost of the TMR. Return over feed cost was computed as revenue minus feed cost.
Statistical Analyses Data were analyzed with generalized least squares ANOVA (mixed procedures of SAS, SAS Inst. Inc., Cary, NC). Milk production and DMI
analysis included the fixed effects of treatment (diet) and period and the repeated effect of day. The covariance structure used to minimize fit statistics was compound symmetry. Ruminal fermentation analysis included the main effects of treatment, period, hour, and treatment × hour with the repeated effect of hour. The covariance structure used to minimize fit statistics was compound symmetry or first-order autoregressive structures. Statistical significance was set at P < 0.05. Tendencies were considered and presented for the reader to discern at P < 0.15 because of the low number of observations in a switchback design.
RESULTS AND DISCUSSION DMI and Milk Yield The chemical composition of the diets and the pelleted, high-oil canola meal is presented in Table 2. Diets were similar in all nutrient contents. There were no differences (P ≥ 0.29) between DMI and milk yield of cows fed the HOCM and the CONT diets (Table 3). A similar DMI and milk yield for the 2 diets indicates that diets were equally palatable and provided similar amounts of nutrients for milk production. Intake of DM was not affected by diets containing 13%
Total ruminal VFA and molar percentages of all VFA except propionate were not changed (P ≥ 0.37) by diets; propionate tended to be increased (P = 0.09) in cows fed HOCM compared with CONT (Table 3). Acetate:propionate ratio was not affected by diet (P = 0.41; Figure 1A); however, there was a treatment × time interaction (P < 0.04). Cows fed the HOCM diet had a lower ratio over time. Isovalerate tended (P = 0.11; Figure 1B) to be less in HOCM-fed cows than in CONT-fed cows as time after feeding progressed. In similar research, the major ruminal VFA concentration was not changed by canola meal (Sanchez and Claypool, 1983; DePeters and Bath, 1986; Brito and Broderick, 2007) compared with that from cows fed soybean meal or cottonseed meal. The 7% inclusion rate of high-oil canola meal did not appear to affect total VFA production; however, propionate concentration tended to be slightly higher with the HOCM diet. This tendency of a slight increase in propionate and decrease in acetate to propionate after feeding could be explained by more ruminal available fat from HOCM than from whole sunflower seeds. Whole oilseeds have slow fat-release properties in the rumen (Shaver, 1990). Also, the tendency of lower isovalerate concen-
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Maiga et al.
Table 3. Dry matter intake, milk production, and ruminal VFA, pH, and ammmonia concentrations for cows fed the control and pelleted, high-oil canola meal (HOCM) diets Treatment (Trt) Item Cows, n DMI, kg/d Milk yield, kg/d Efficiency, kg of milk/kg of DMI VFA, mol/100 mol Acetate Propionate Butyrate Isobutyrate Valerate Isovalerate Total VFA, mM Acetate:propionate pH NH3, mM
Control
HOCM
4 26.3 43.5 1.65
4 24.9 45.4 1.82
54.91 19.59 12.47 3.23 4.52 5.28 114.3 2.91 6.02 18.76
54.21 21.36 12.19 3.09 4.41 4.75 107.7 2.57 6.02 17.15
P-value SEM
0.8 5.9 0.18 1.19 0.70 0.51 0.11 0.17 0.38 5.8 0.27 0.09 1.30
Trt
0.29 0.84 0.54 0.69 0.09 0.71 0.43 0.68 0.37 0.46 0.41 0.96 0.42
Time, h
Trt × time
<0.001 0.49 0.006 <0.001 <0.001 <0.001 0.01 <0.001 <0.001 <0.001
0.32 0.94 0.46 0.57 0.39 0.11 0.74 0.04 0.14 0.09
tration over time could be explained by slower availability of leucine and isoleucine ruminally (Allison, 1969) from the HOCM because of heat damage to the protein.
Ruminal pH Average ruminal pH was 6.02 (Table 3) but tended to be affected differently over time by diet (P = 0.14; Figure 1C). Ruminal pH tended to be more acidic for HOCM-fed cows at feeding and was not different thereafter. Ruminal pH was unaffected by canola meal in previous research (Sanchez and Claypool, 1983; DePeters and Bath, 1986; Brito and Broderick, 2007). When ruminal pH was measured over time, the mean ruminal pH was near or a little above 6.0 (Casper et al., 1999; Brito and Broderick, 2007) for cows fed diets containing more than 40% nonfiber carbohydrates. This observation is especially valid during the first 12 h after feeding (as diagrammed by Casper et al., 1999; Brito and Broderick, 2007), because ruminal pH is usually high at feeding; then declines until about 12 h postfeeding; and then increases as a result of more rumination, saliva production, and ruminal absorption of
Figure 1. The effect of feeding a control (CONT; ♦) or pelleted, high-oil canola meal (HOCM; ■) diet on ruminal acetate:propionate ratio (A), isovalerate (B), pH (C), and ammonia (D); bars represent SE.
Effect of pelleted high-oil canola meal on rumen fermentation
VFA. Ruminal pH declining over the first 8 h after feeding both diets was in agreement with results reported by Casper et al. (1999) and Brito and Broderick (2007).
Ruminal Ammonia Ruminal ammonia concentration was similar among treatments but tended to be affected differently over time by the diets (P = 0.09; Figure 1D); ruminal ammonia was lower for HOCM than for CONT at 8 h after feeding. Studies (Sanchez and Claypool, 1983; DePeters and Bath, 1986; Brito and Broderick, 2007) involving low-oil canola meal feeding showed no differences in ammonia production when compared with other plantprotein supplements. This result is in agreement with our data. This also would indicate that rumen degradability of protein and microbial use of nitrogen for protein synthesis or ammonia absorption were similar between diets. The fact that feed and nutrient intake was not different and ruminal fermentation data were not remarkably different leads to the conclusion that concentration of milk components (not measured in this study) would not be affected by diets.
Return over Feed Cost Returns over feed cost based on United States dollars for the 2 diets
are in Table 4. Estimated revenue was $0.75/d greater for HOCM than for CONT. The daily feed cost was $5.65/d for the CONT diet and $4.98/d for the HOCM diet, resulting in a difference of $0.67/d lower cost for the HOCM diet. Therefore, estimated return from the HOCM diet was $1.42/d greater than that from the control diet. The difference of $1.42 more return per day for the HOCM diet translates into $433.10 per 305-d lactation. Milk and feed ingredients prices are determined by the market and are dynamic; a price change could change the result of this economic assessment. Because of the preliminary nature of this study and limited observations, this result should be interpreted with caution; however, there appears to be an economic advantage of feeding HOCM.
IMPLICATIONS Feeding 7% of pelleted, high-oil canola meal in lactating Holstein dairy cow diets did not adversely affect ruminal VFA concentration, pH, or ammonia concentration. There was a slight tendency of an increase in ruminal propionate concentration. Milk production and DMI were not affected. Pelleted high-oil and highprotein canola meal is a good energy and protein source for lactating dairy cows. At current local feed ingredi-
Table 4. Return over feed cost (ROFC) for the control and pelleted, high-oil canola meal (HOCM) diets Diet Control HOCM
Revenue, 1 $/d
Feed cost, 2 $/d
ROFC, 3 $/d
17.23 17.98
5.65 4.98
11.58 13.00
Price of milk sold was at $0.396/kg of milk. Revenue ($/d) equals milk yield (kg/d) × $0.396/kg.
1
Feed prices per 100 kg of feed DM: alfalfa haylage, $8.8; corn silage, $6.6; highmoisture shelled corn, $24.7; soybean meal, $51.9; whole sunflower oil seed, $65.2; dried distillers grains, $26.5; pelleted canola meal, $33.8; dicalcium phosphate, $142.6; sodium bicarbonate, $61.0; calcium carbonate, $25.0; trace mineralized salt, $28.0; and vitamin ADE mix, $80.5. Feed cost ($/d) equals DMI (kg/d) × $/kg of feed DM (control: 26.3 kg/d × $0.215/kg and HOCM: 24.9 kg/d × $0.20/kg).
2
3
ROFC ($/d) = revenue − feed cost (Maiga et al. 1995).
33
ents and milk prices, there appears to be an economic advantage of feeding the HOCM diet compared with the CONT diet, which may benefit on-farm biodiesel production. Future studies including different feeding levels of high-oil canola meal are warranted to assess trends observed in VFA data and to reevaluate the economic value of high-oil canola meal.
ACKNOWLEDGMENTS This research was supported by a University of Minnesota, Crookston Student Research Grant. The authors would like to thank the University of Minnesota Northwest Research and Outreach Center Barn Crew, Jayme Wilkens (North Dakota State University, Fargo), and Paul Aakre (University of Minnesota, Crookston) for all their help with data collection and summarization.
LITERATURE CITED Allison, M. J. 1969. Biosynthesis of amino acids by ruminal microorganisms. J. Anim. Sci. 29:797. AOAC. 1997. Official Methods of Analysis. 16th ed., 3rd rev. AOAC, Gaithersburg, MD. Bell, J. M. 1984. Nutrients and toxicants in rapeseed meal: A review. J. Anim. Sci. 58:996. Brito, A. F., and G. A. Broderick. 2007. Effects of different protein supplements on milk production and nutrient utilization in lactating dairy cows. J. Dairy Sci. 90:1816. Casper, D. P., H. A. Maiga, M. J. Brouk, and D. J. Schingoethe. 1999. Synchronization of carbohydrate and protein sources and passage rates in dairy cows. J. Dairy Sci. 82:1779. Chichlowski, M. W., J. W. Schroeder, C. S. Park, W. L. Keller, and D. E. Schimek. 2005. Altering the fatty acids in milk fat by including canola seed in dairy cattle diets. J. Dairy Sci. 88:3084. DePeters, E. J., and D. L. Bath. 1986. Canola meal versus cottonseed meal as the protein supplement in dairy diets. J. Dairy Sci. 69:148. Lucas, H. L. 1956. Switchback trials for more than two treatments. J. Dairy Sci. 39:146. Lucas, H. L. 1960. Critical features of good dairy feeding experiments. J. Dairy Sci. 43:193. Maesoomi, S. M., G. R. Ghorbani, M. Alikhani, and A. Nikkhah. 2006. Short com-
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munication: Canola meal as a substitute for cottonseed meal in diet of midlactation Holsteins. J. Dairy Sci. 89:1673.
NRC. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Acad. Press, Washington, DC.
Maiga, H. A., D. J. Schingoethe, and F. C. Ludens. 1995. Evaluation of diets containing supplemental fat with different sources of carbohydrates for lactating dairy cows. J. Dairy Sci. 78:1122.
Piepenbrink, M. S., and D. J. Schingoethe. 1998. Ruminal degradation, amino acid composition, and estimated intestinal digestibilities of four protein supplements. J. Dairy Sci. 81:454.
NRC. 1989. Nutrient Requirements of Dairy Cattle. 6th rev. ed. Natl. Acad. Press, Washington, DC.
Sanchez, J. M., and D. W. Claypool. 1983. Canola meal as a protein supplement in dairy rations. J. Dairy Sci. 66:80.
Shaver, R. D. 1990. Fat sources for high producing dairy cows. p. 13 in Proceedings of the 51st Minnesota Nutrition Conference. Minnesota Extension Service, Bloomington, MN. Van Soest, P. J., J. B. Robertson, and B. A. Lewis. 1991. Methods of dietary fiber, neutral detergent, and non-starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74:3583.
©2011 American Registry of Professional Animal Scientists
E fcanola fect of pelleted high-oil meal from on-farm
biodiesel production on rumen fermentation in lactating Holstein dairy cows H. A. Maiga,*1 D. M. Harris,* M. E. Meyer,* C. R. Dahlen,† and M. L. Bauer† *Department of Agriculture, Animal Science Division, University of Minnesota, Crookston 56716; †Department of Animal Sciences, North Dakota State University, Fargo 58108-6050
ABSTRACT Four lactating, ruminally cannulated Holstein cows (DIM ≥50; ≥second lactation) were paired by milk production and used in a switchback design to compare ruminal fermentation response to a diet containing 7% pelleted, high-oil canola meal (HOCM) versus a control diet (CONT). The CONT diet was made of corn silage, alfalfa haylage, wheat straw, and the concentrate. The HOCM diet contained the same ingredients as the CONT except sunflower seeds and a portion of soybean meal were replaced with pelleted, high-oil canola meal in the concentrate. The canola pellet contained 16.6% crude fat and 37.3% CP. Diets were formulated to be isonitrogenous and isocaloric. The last day of each 21-d switchback period was used to collect ruminal fermentation data. Ruminal fluid samples were collected through the cannula at 0, 2, 4, 6, and 8 h after feeding. Cows were housed in a tie-stall barn, and diets were delivered as a TMR once daily at 1000 h to achieve ad libitum intake (5% orts). Daily DMI and milk producCorresponding author: [email protected]
1
tion data were recorded during the entire feeding period. There were no differences (P ≥ 0.29) between DMI, milk yield, and efficiency of milk production of cows fed the HOCM and the CONT diets. Ruminal acetate, butyrate, total VFA, and pH were not affected (P ≥ 0.37) by diets. Ruminal propionate tended to be greater (P = 0.09) in cows fed HOCM. Adding 7% of pelleted, high-oil canola meal to lactating Holstein dairy cow diets did not adversely affect ruminal fermentation. Key words: biodiesel coproduct, lactating dairy cow, pelleted high-oil canola meal, ruminal fermentation
INTRODUCTION The increasing need for energy production has generated interest in small-scale on-farm biofuel production from oilseed crops. Specifically, the growing demand for biodiesel has provided the opportunity to crush canola seed for this purpose. In 2006, several farmers in Minnesota and Wisconsin began crushing canola with small-scale on-farm oilseed presses. The mechanical process removes oil
from the seed with the coproduction of a protein pellet that contains greater concentrations of residual oil compared with solvent-extracted canola meal. The protein pellet obtained from our pilot production plant contained 16.6% crude fat and 37.3% CP (DM basis). The daily quantity of protein pellet produced was 320 kg or 115 t yearly per processing unit. The use of the term canola meal throughout the text refers to low-fat canola meal, either solvent or mechanically extracted. In contrast, commercially available, solvent-extracted canola meal contains less ether extract (4%), which is higher than other oilseed meals because of inclusion of 1.5% of gums (Sanchez and Claypool, 1983). Sanchez and Claypool (1983) also reported that the protein content of canola meal varies from 35 to 39% depending on the cultivar used. The amino acid profile of the RUP fraction of canola meal mimics the milk protein amino acids, and the RDP fraction may stimulate microbial growth in the rumen (Piepenbrink and Schingoethe, 1998). The pelleted high-oil and high-
30 protein canola meal contains slightly more energy (2.43 Mcal/kg) in terms of NEl at 3 times maintenance intake than does soybean meal (2.13 Mcal/ kg; NRC, 2001) or canola meal (1.57 Mcal/kg; NRC, 1989). Regular canola meal is an excellent and safe protein supplement for dairy cows (Bell, 1984; Maesoomi et al., 2006) compared with its parental rapeseed meal. To our knowledge, no studies have been conducted on this novel biodiesel coproduct feed ingredient. The objective of this study was to evaluate ruminal VFA, pH, and ammonia-concentration responses to a diet containing 7% pelleted, high-oil canola meal versus a control diet, when diets were balanced to be isonitrogenous and isocaloric. We hypothesized that ruminal fermentation response of cows fed the 2 diets would be similar.
MATERIALS AND METHODS Animals and Treatments The use and handling procedures of animals used in this study were approved by the University of Minnesota Animal Care and Use Committee. Four lactating, ruminally cannulated
Maiga et al.
Holstein cows (DIM ≥50) in second or higher lactation were paired by milk production (≥30 kg/d) and assigned to one of 2 diets in a switchback design (Lucas, 1956; Lucas, 1960) of 2 periods of 21 d each. The ingredient composition of the diets is presented in Table 1. The forage portion of the control (CONT) diet contained alfalfa haylage, corn silage, and wheat straw and the concentrate portion contained rolled, high-moisture corn, soybean meal, sunflower seeds, dried distillers grains with solubles, minerals, and vitamins. The pelleted, high-oil canola meal (HOCM) diet contained the same ingredients as the CONT diet except sunflower seeds and a portion of soybean meal were replaced with pelleted, high-oil canola meal. The pellet contained 16.6% crude fat and 37.3% CP. Diets were formulated to contain 18% CP and 1.74 Mcal/kg of NEl, which called for a 7% canola meal inclusion rate in the HOCM diet. Diets were also formulated to provide a similar amount of total crude fat. Cows were housed in a tie-stall barn, and diets were delivered as a TMR once daily at 1000 h to achieve ad libitum intake (5% orts). Amounts of feed fed and orts were recorded daily to determine DMI.
Table 1. Ingredients composition of TMR for cows fed the control or the pelleted, high-oil canola meal (HOCM) diets Ingredient, % of dietary DM Alfalfa haylage Corn silage Wheat straw High-moisture corn (73.3% DM) Soybean meal (44% CP) Sunflower seed Dried corn distillers grains Pelleted canola meal (expeller) Dicalcium phosphate (CaHPO4) Sodium bicarbonate (NaHCO3) Calcium carbonate (CaCO3) Trace-mineralized salt1 Vitamin ADE2
Control
HOCM
25.0 25.0 2.0 21.1 13.0 2.8 8.5 — 0.3 1.0 0.5 0.6 0.2
24.9 24.9 2.0 21.0 9.1 — 8.5 7.0 0.3 1.0 0.5 0.6 0.2
Provided per kilogram of dietary DM: 36.5 mg of Zn, 26.0 mg of Mn, 20.5 mg of Fe, 9.1 mg of Cu, 0.6 mg of I, 0.4 mg of Co, and 0.3 mg of Se.
1
Provided per kilogram of dietary DM: 6,875 IU of supplemental vitamin A, 1,379 IU of supplemental vitamin D, and 23 IU of supplemental vitamin E.
2
Sample Collection and Chemical Analyses Samples of TMR, alfalfa haylage, corn silage, wheat straw, concentrates, and pelleted canola meal were collected once weekly during each feeding period and frozen at −20°C until analysis. Samples were oven dried at 55°C and ground through a Wiley mill (1-mm screen; Arthur H. Thomas, Philadelphia, PA). All samples were analyzed for DM, CP, ether extract, ash, ADL, calcium, and phosphorus (methods 930.15, 990.02, 945.16, 942.05, 973.18, 968.08, and 965.07, respectively; AOAC, 1997). The NDF (with amylase and without sulfite) and ADF were analyzed with a fiber analysis unit (Ankom Technology, Fairport, NY) using the procedure of Van Soest et al. (1991). Samples of whole ruminal contents (about 200 mL) were collected through the cannula from the ventral sac of the rumen of the 4 cows on d 21 of each period. Samples were taken at 0, 2, 4, 6, and 8 h relative to feeding. Samples were strained through layers of cheesecloth, followed immediately by pH measurement of ruminal fluid using a sealed electrode (Orion Research model 701A meter, Waltham, MA). A 50-mL ruminal fluid sample was frozen for later determination of VFA and ammonia. Ammonia concentration at each sampling hour was determined by colorimetric procedure (procedure 640 with urease hydrolysis omitted, Sigma Chemical Co., St. Louis, MO), and VFA were determined by GLC as described by Chichlowski et al. (2005). Daily DMI and milk production data were recorded during each feeding period. Cows were milked twice daily, and milk weights were recorded at each milking during the entire trial period. To eliminate carryover effects of diets, only data from the last 14 d of each period were used to determine DMI and milk yield.
Effect of pelleted high-oil canola meal on rumen fermentation
Table 2. Chemical composition of control and high-oil canola meal (HOCM) diets and the pelleted, high-oil canola meal (DM basis) Item DM, % CP, % NEl,1 Mcal/kg Ether extract, % NDF, % ADF, % Lignin, % NFC,2 % Ash, % Ca, % P, % 1
Control
HOCM
Canola meal pellet
57.1 18.1 1.74 4.8 28.7 17.6 3.7 41.1 7.3 0.96 0.48
57.3 18.2 1.74 4. 7 28.8 17.8 3.8 41.0 7.5 0.95 0.49
92.9 37.3 2.43 16.6 18.5 14.3 8.7 22.3 5.3 0.45 0.76
Calculated using NEl equations for feedstuffs from NRC (2001).
NFC (nonfiber carbohydrates) = 100 − (% NDF + % CP + % fat + % ash) according to the NRC (2001) model.
2
31
(DePeters and Bath, 1986) or 14% canola meal (Chichlowski et al., 2005; Maesoomi et al., 2006). However, Brito and Broderick (2007) found a 0.70 kg/d greater DMI by Holstein cows fed 16% canola meal than by cows fed 12% soybean meal but no difference in milk yield between the 2 treatments. Milk production of Holstein cows fed 11.7% canola meal was similar to that of cows fed 10.4% cottonseed or 8.6% soybean meal (Sanchez and Claypool, 1983).Yield of milk components was not affected by canola meal (DePeters and Bath, 1986; Chichlowski et al., 2005). Milk production efficiency (kg of milk/kg of DMI) was not different (P = 0.54) among diets.
Ruminal VFA Return over Feed Cost Calculation The cost–benefit analysis method (Maiga et al., 1995) was used to determine returns on feeding the HOCM diet versus the CONT diet. The difference between the daily revenue (benefit) and the cost is the return on feeding a given diet. Return over feed cost was calculated by using local prices of feed ingredients and milk price received for milk sold at the time of the study. The pelleted, high-oil canola meal was priced based on local average price of commercially available solvent-extracted canola meal relative to its NEl with the assumption that both canola meals would have similar protein content. Revenue from both diets was calculated by multiplying the average quantity of milk produced by the 4 cows times milk price. Feed cost was calculated by multiplying the average quantity of DMI of the 4 cows times the daily cost of the TMR. Return over feed cost was computed as revenue minus feed cost.
Statistical Analyses Data were analyzed with generalized least squares ANOVA (mixed procedures of SAS, SAS Inst. Inc., Cary, NC). Milk production and DMI
analysis included the fixed effects of treatment (diet) and period and the repeated effect of day. The covariance structure used to minimize fit statistics was compound symmetry. Ruminal fermentation analysis included the main effects of treatment, period, hour, and treatment × hour with the repeated effect of hour. The covariance structure used to minimize fit statistics was compound symmetry or first-order autoregressive structures. Statistical significance was set at P < 0.05. Tendencies were considered and presented for the reader to discern at P < 0.15 because of the low number of observations in a switchback design.
RESULTS AND DISCUSSION DMI and Milk Yield The chemical composition of the diets and the pelleted, high-oil canola meal is presented in Table 2. Diets were similar in all nutrient contents. There were no differences (P ≥ 0.29) between DMI and milk yield of cows fed the HOCM and the CONT diets (Table 3). A similar DMI and milk yield for the 2 diets indicates that diets were equally palatable and provided similar amounts of nutrients for milk production. Intake of DM was not affected by diets containing 13%
Total ruminal VFA and molar percentages of all VFA except propionate were not changed (P ≥ 0.37) by diets; propionate tended to be increased (P = 0.09) in cows fed HOCM compared with CONT (Table 3). Acetate:propionate ratio was not affected by diet (P = 0.41; Figure 1A); however, there was a treatment × time interaction (P < 0.04). Cows fed the HOCM diet had a lower ratio over time. Isovalerate tended (P = 0.11; Figure 1B) to be less in HOCM-fed cows than in CONT-fed cows as time after feeding progressed. In similar research, the major ruminal VFA concentration was not changed by canola meal (Sanchez and Claypool, 1983; DePeters and Bath, 1986; Brito and Broderick, 2007) compared with that from cows fed soybean meal or cottonseed meal. The 7% inclusion rate of high-oil canola meal did not appear to affect total VFA production; however, propionate concentration tended to be slightly higher with the HOCM diet. This tendency of a slight increase in propionate and decrease in acetate to propionate after feeding could be explained by more ruminal available fat from HOCM than from whole sunflower seeds. Whole oilseeds have slow fat-release properties in the rumen (Shaver, 1990). Also, the tendency of lower isovalerate concen-
32
Maiga et al.
Table 3. Dry matter intake, milk production, and ruminal VFA, pH, and ammmonia concentrations for cows fed the control and pelleted, high-oil canola meal (HOCM) diets Treatment (Trt) Item Cows, n DMI, kg/d Milk yield, kg/d Efficiency, kg of milk/kg of DMI VFA, mol/100 mol Acetate Propionate Butyrate Isobutyrate Valerate Isovalerate Total VFA, mM Acetate:propionate pH NH3, mM
Control
HOCM
4 26.3 43.5 1.65
4 24.9 45.4 1.82
54.91 19.59 12.47 3.23 4.52 5.28 114.3 2.91 6.02 18.76
54.21 21.36 12.19 3.09 4.41 4.75 107.7 2.57 6.02 17.15
P-value SEM
0.8 5.9 0.18 1.19 0.70 0.51 0.11 0.17 0.38 5.8 0.27 0.09 1.30
Trt
0.29 0.84 0.54 0.69 0.09 0.71 0.43 0.68 0.37 0.46 0.41 0.96 0.42
Time, h
Trt × time
<0.001 0.49 0.006 <0.001 <0.001 <0.001 0.01 <0.001 <0.001 <0.001
0.32 0.94 0.46 0.57 0.39 0.11 0.74 0.04 0.14 0.09
tration over time could be explained by slower availability of leucine and isoleucine ruminally (Allison, 1969) from the HOCM because of heat damage to the protein.
Ruminal pH Average ruminal pH was 6.02 (Table 3) but tended to be affected differently over time by diet (P = 0.14; Figure 1C). Ruminal pH tended to be more acidic for HOCM-fed cows at feeding and was not different thereafter. Ruminal pH was unaffected by canola meal in previous research (Sanchez and Claypool, 1983; DePeters and Bath, 1986; Brito and Broderick, 2007). When ruminal pH was measured over time, the mean ruminal pH was near or a little above 6.0 (Casper et al., 1999; Brito and Broderick, 2007) for cows fed diets containing more than 40% nonfiber carbohydrates. This observation is especially valid during the first 12 h after feeding (as diagrammed by Casper et al., 1999; Brito and Broderick, 2007), because ruminal pH is usually high at feeding; then declines until about 12 h postfeeding; and then increases as a result of more rumination, saliva production, and ruminal absorption of
Figure 1. The effect of feeding a control (CONT; ♦) or pelleted, high-oil canola meal (HOCM; ■) diet on ruminal acetate:propionate ratio (A), isovalerate (B), pH (C), and ammonia (D); bars represent SE.
Effect of pelleted high-oil canola meal on rumen fermentation
VFA. Ruminal pH declining over the first 8 h after feeding both diets was in agreement with results reported by Casper et al. (1999) and Brito and Broderick (2007).
Ruminal Ammonia Ruminal ammonia concentration was similar among treatments but tended to be affected differently over time by the diets (P = 0.09; Figure 1D); ruminal ammonia was lower for HOCM than for CONT at 8 h after feeding. Studies (Sanchez and Claypool, 1983; DePeters and Bath, 1986; Brito and Broderick, 2007) involving low-oil canola meal feeding showed no differences in ammonia production when compared with other plantprotein supplements. This result is in agreement with our data. This also would indicate that rumen degradability of protein and microbial use of nitrogen for protein synthesis or ammonia absorption were similar between diets. The fact that feed and nutrient intake was not different and ruminal fermentation data were not remarkably different leads to the conclusion that concentration of milk components (not measured in this study) would not be affected by diets.
Return over Feed Cost Returns over feed cost based on United States dollars for the 2 diets
are in Table 4. Estimated revenue was $0.75/d greater for HOCM than for CONT. The daily feed cost was $5.65/d for the CONT diet and $4.98/d for the HOCM diet, resulting in a difference of $0.67/d lower cost for the HOCM diet. Therefore, estimated return from the HOCM diet was $1.42/d greater than that from the control diet. The difference of $1.42 more return per day for the HOCM diet translates into $433.10 per 305-d lactation. Milk and feed ingredients prices are determined by the market and are dynamic; a price change could change the result of this economic assessment. Because of the preliminary nature of this study and limited observations, this result should be interpreted with caution; however, there appears to be an economic advantage of feeding HOCM.
IMPLICATIONS Feeding 7% of pelleted, high-oil canola meal in lactating Holstein dairy cow diets did not adversely affect ruminal VFA concentration, pH, or ammonia concentration. There was a slight tendency of an increase in ruminal propionate concentration. Milk production and DMI were not affected. Pelleted high-oil and highprotein canola meal is a good energy and protein source for lactating dairy cows. At current local feed ingredi-
Table 4. Return over feed cost (ROFC) for the control and pelleted, high-oil canola meal (HOCM) diets Diet Control HOCM
Revenue, 1 $/d
Feed cost, 2 $/d
ROFC, 3 $/d
17.23 17.98
5.65 4.98
11.58 13.00
Price of milk sold was at $0.396/kg of milk. Revenue ($/d) equals milk yield (kg/d) × $0.396/kg.
1
Feed prices per 100 kg of feed DM: alfalfa haylage, $8.8; corn silage, $6.6; highmoisture shelled corn, $24.7; soybean meal, $51.9; whole sunflower oil seed, $65.2; dried distillers grains, $26.5; pelleted canola meal, $33.8; dicalcium phosphate, $142.6; sodium bicarbonate, $61.0; calcium carbonate, $25.0; trace mineralized salt, $28.0; and vitamin ADE mix, $80.5. Feed cost ($/d) equals DMI (kg/d) × $/kg of feed DM (control: 26.3 kg/d × $0.215/kg and HOCM: 24.9 kg/d × $0.20/kg).
2
3
ROFC ($/d) = revenue − feed cost (Maiga et al. 1995).
33
ents and milk prices, there appears to be an economic advantage of feeding the HOCM diet compared with the CONT diet, which may benefit on-farm biodiesel production. Future studies including different feeding levels of high-oil canola meal are warranted to assess trends observed in VFA data and to reevaluate the economic value of high-oil canola meal.
ACKNOWLEDGMENTS This research was supported by a University of Minnesota, Crookston Student Research Grant. The authors would like to thank the University of Minnesota Northwest Research and Outreach Center Barn Crew, Jayme Wilkens (North Dakota State University, Fargo), and Paul Aakre (University of Minnesota, Crookston) for all their help with data collection and summarization.
LITERATURE CITED Allison, M. J. 1969. Biosynthesis of amino acids by ruminal microorganisms. J. Anim. Sci. 29:797. AOAC. 1997. Official Methods of Analysis. 16th ed., 3rd rev. AOAC, Gaithersburg, MD. Bell, J. M. 1984. Nutrients and toxicants in rapeseed meal: A review. J. Anim. Sci. 58:996. Brito, A. F., and G. A. Broderick. 2007. Effects of different protein supplements on milk production and nutrient utilization in lactating dairy cows. J. Dairy Sci. 90:1816. Casper, D. P., H. A. Maiga, M. J. Brouk, and D. J. Schingoethe. 1999. Synchronization of carbohydrate and protein sources and passage rates in dairy cows. J. Dairy Sci. 82:1779. Chichlowski, M. W., J. W. Schroeder, C. S. Park, W. L. Keller, and D. E. Schimek. 2005. Altering the fatty acids in milk fat by including canola seed in dairy cattle diets. J. Dairy Sci. 88:3084. DePeters, E. J., and D. L. Bath. 1986. Canola meal versus cottonseed meal as the protein supplement in dairy diets. J. Dairy Sci. 69:148. Lucas, H. L. 1956. Switchback trials for more than two treatments. J. Dairy Sci. 39:146. Lucas, H. L. 1960. Critical features of good dairy feeding experiments. J. Dairy Sci. 43:193. Maesoomi, S. M., G. R. Ghorbani, M. Alikhani, and A. Nikkhah. 2006. Short com-
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NRC. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Acad. Press, Washington, DC.
Maiga, H. A., D. J. Schingoethe, and F. C. Ludens. 1995. Evaluation of diets containing supplemental fat with different sources of carbohydrates for lactating dairy cows. J. Dairy Sci. 78:1122.
Piepenbrink, M. S., and D. J. Schingoethe. 1998. Ruminal degradation, amino acid composition, and estimated intestinal digestibilities of four protein supplements. J. Dairy Sci. 81:454.
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Sanchez, J. M., and D. W. Claypool. 1983. Canola meal as a protein supplement in dairy rations. J. Dairy Sci. 66:80.
Shaver, R. D. 1990. Fat sources for high producing dairy cows. p. 13 in Proceedings of the 51st Minnesota Nutrition Conference. Minnesota Extension Service, Bloomington, MN. Van Soest, P. J., J. B. Robertson, and B. A. Lewis. 1991. Methods of dietary fiber, neutral detergent, and non-starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74:3583.